Abstract

It is often anticipated that the linear optical properties of GaAs as a cubic material are isotropic. More careful consideration shows that spatial dispersion terms lead to a small linear birefringence in this crystal. However, the nonlinear optical response is by no means isotropic. Local and nonlocal nonlinear anisotropy lead to the dependence of the efficiency of the two-photon absorption process on the crystal orientation and to a variety of nonlinear polarization-affecting phenomena for propagating light. Here we report the first observation of a new small, but detectable pump–probe polarization sensitive transient effect in reflected light, which results directly from the anisotropy of the zinc-blended structure. We compare these results with the new data on transient nonresonant Specular Inverse Faraday effect, which we observed recently.¹ This polarization altering effect has the potential to become a new method for the investigation of cubic crystal anisotropy and nonlocality and is especially suitable for nontransparent materials, such as narrow-gap semiconductors, and superconductors where the application of transmission methods is not possible.

© 1994 IEEE